In this post, we will get to know the species of Birds that catch fish and a little of their fishing methods. We will also understand a little about their biology and ecology.
Which Birds love catching fish?
Seabirds are those species that have adapted very efficiently to the marine environment and have the sea as their habitat and/or food source, including fish-based food.
Despite the large amount and potential diversity of available food, seabirds account for just over 3% of the known bird species. They can be divided into coastal seabirds – usually found close to the continents, and oceanic or pelagic seabirds – usually found in the high seas.
In general, these birds have more feathers than land birds and their wings and feathers are impregnated with grease that makes them waterproof. These two characteristics allow these animals to spend their entire lives in the sea without practically getting wet.
To help with swimming, they usually have an interdigital membrane on their feet. Many species, such as albatrosses, have a small tube above the beak that serves to excrete excess salt ingested.
Sea birds and their characteristics
Some of the characteristics of seabirds make them excellent ecological bioindicators. They are quite visible, in an environment where most other organisms are located below the water column, they are easy to identify, most species are colonial and reproduce annually in large numbers and determined locations.
They are relatively easy to capture during the breeding season and have a long lifespan and, therefore, are sensitive to cumulative environmental impacts.
These birds can constitute two main types of ecosystem indicators: sentinels (species introduced to indicate levels of degradation) of environmental variations, such as pollution levels indicated by tissue analysis, such as feathers and quantitative indicators of specific elements of the ecosystem, such as the abundance of a particular species of fish.
Seabirds have several characteristics that allow them to be so successful in the environment in which they live.
There are at least 310 species of existing seabirds distributed in four orders:
· Sphenisciformes (penguins)
· Procellariiformes
· Pelecaniformes (pelicans, grebes and frigates)
· Charadriiforms
Sphenisciformes
Currently comprising 18 species grouped in the Spheniscidae family, penguins occur from the Antarctic continent to tropical areas.
They are seabirds adapted for diving and swimming whose forelegs are modified into fins. They also have well-developed nasal glands for salt excretion.
They go ashore only during reproduction or when exhausted, forming large colonies. They have short legs with an interdigital membrane between the toes and scale-like feathers. They feed on a wide variety of prey such as small fish and squid.
Procellariiformes
Composed of 4 families and 108 species in the world, including the Royal Albatross. This group gathers most of the sea birds. They are oceanic or pelagic and generally found in the southern hemisphere.
The members of this order are known for their maxillary and mandibular ramphotheques composed of several distinct plates, the hook-shaped tip of the maxilla to capture smooth and fast prey, the tube-shaped nostrils for salt excretion and the paws used for swimming, take-off, and water landing.
Pelecaniformes
The Pelecaniformes are sea birds that include 5 families. Most of them are piscivorous (feed on fish).
Among the Pelecaniformes, tropical birds (Phaethontidae), frigates, and sulids are exclusively seabirds. The diverse species of cormorants, anhingas, and pelicans can be exclusively marine or freshwater birds, or they can thrive in both environments.
They have four toes connected by membranes (totipalmate). The incubation plate is absent. While the salt gland of most seabirds is in a cavity at the top of the skull, the Pelecaniformes salt gland is completely enclosed in the orbit. Most of them have an exposed gular pouch, except for tropical birds, where this structure is inconspicuous and feathered.
Charadriiformes
Charadriiformes is a highly diverse order of birds, second only to Passeriformes in the number of families and species. This group is divided, mainly, between the considered shorebirds, such as the stone curlews, the curlews and the jacanas, and the other 5 groups of seabirds, which include the seagulls, the terns, and the mandrills.
Species of this order have diverse and complex behaviours regarding the formation of couples and egg-laying, as well as great diversity regarding their body shape, leg length and beak style.
Most of these seabirds tend to form colonies at the time of mating, while waders tend to behave solitary, and have developed more complex reproductive behaviours, polygamy, and parental care by only one parent.
The diversity of charadriiforms can be very well observed when analysing the variety of their diets and foraging strategies. Diets vary between animals and vegetables, and in some cases, it is highly specialized.
Many are piscivores, but their strategies for capturing prey vary; seagulls have long, slender wings, adapted to diving quickly into water and catching fish close to the surface, while all have short, strong wings that are used to swim underwater in search of prey. As for aquatic and terrestrial invertebrates, the one that developed the greatest diversity in the collection of this food was the group of shorebirds, with great diversity in the morphology of their beaks and legs.
Reproductive behaviour and Parental care
Most of them get a mate in the following steps: A male claims territory within the colony and woos females, who go into the territories and interact with the males. Male frigates select another location if they are not successful in obtaining a mate.
The chicks are altricial, that is, they hatch naked and helpless, presenting a faster growth rate compared to the semi-precocial Charadriiformes, which hatch with a complete layer of down and locomotion capacity.
Chicks are normally assisted by at least one parent during the first quarter to third of the nesting period, which results in a relatively long period before the youngsters become endothermic. On the other hand, this pattern may simply reflect the fact that both parents do not need to look for food at the same time. In species such as gannets, which form dense colonies, unaccompanied chicks are often attacked by neighbouring adults and are therefore rarely left alone in the nest. In other species, chicks are left gradually alone as they grow. Parental care after the onset of plumage in chicks is quite common. Large frigates with a parental care period of more than 400 days have been reported in some cases.
The fundamental relationship between sexual partners is monogamy. The common frigate male (Fregata magnificens) is an exception, abandoning a breeding cycle in the middle, theoretically free to start a new one with another female next year, while the previous female continues to rear her young.
Seabirds salt gland
Some species of seabirds, which ingest saltwater fish and seawater, have the salt gland, located near the animal’s eyes or nostrils. The salt ingested by the animal falls into the bloodstream and is taken to the glands to be eliminated. Excess salt can also be eliminated through the nostrils of the animal in liquid form. The structure of the salt gland is similar to the structure of mammalian kidneys.
Conclusion
In this post, we met the species of Birds that catch fish and a little of their fishing methods. We also understood a little about their biology and ecology.
If you have any thoughts or doubts, feel free to drop us in a comment below!
Frequently Asked Questions (FAQs): Bird catching fish
What are seabirds?
Seabirds refer to about 350 species in total that live near water and relies their life cycle entirely or partially on the seawater.
What birds eat fish?
Piscivorous birds are the ones that eat fish, such as pelicans, frigates, and a few ducks. Other species of birds can also feed on fish, such as penguins.
What is the Albatross bird?
Albatrosses are large birds that belong to the Diomedeidae family, order Procellariiformes. They are seabirds extremely adapted to life on the high seas. They are found on land only during the breeding season.
How do seabirds release excess salt?
Some species of seabirds, which ingest saltwater fish and seawater, have a salt gland, located near the animal’s eyes or nostrils. The salt ingested by the animal falls into the bloodstream and is taken to the glands to be eliminated. Excess salt can also be eliminated through the nostrils of the animal in liquid form.
How does the salt gland work?
The salt gland drains the excess of salt through a duct in the posterior corner of the eye or nostrils in seabirds, this duct converges to the exterior of the birds’ body. This duct, when interiorizing the gland, is subdivided into the main duct, secondary ducts and central channels.
References
Furness, R. W. (2012). Seabird ecology. Springer Science & Business Media.
Anderson, O. R., Small, C. J., Croxall, J. P., Dunn, E. K., Sullivan, B. J., Yates, O., & Black, A. (2011). Global seabird bycatch in longline fisheries. Endangered Species Research, 14(2), 91-106.
Ashmole, N. P., Farner, D. S., & King, J. R. (1971). Seabird ecology and the marine environment. Avian biology, 1, 223-286.
Furness, R. W. (2003). Impacts of fisheries on seabird communities. Scientia Marina, 67(S2), 33-45.
